don't allow to finalize a logbook entry more than once

src/model/logbook.rs

@@ -126,6 +126,7 @@ pub enum LogbookUpdateError {
     UserNotAllowedToUseBoat,
     OnlyAllowedToEndTripsEndingToday,
     TooFast(i64, i64),
+    AlreadyFinalized,
 }
 
 #[derive(Debug, PartialEq)]
@@ -150,6 +151,7 @@ pub enum LogbookCreateError {
     OnlyAllowedToEndTripsEndingToday,
     CantChangeHandoperatableStatusForThisBoat,
     TooFast(i64, i64),
+    AlreadyFinalized,
 }
 
 impl From<LogbookUpdateError> for LogbookCreateError {
@@ -174,6 +176,7 @@ impl From<LogbookUpdateError> for LogbookCreateError {
                 LogbookCreateError::OnlyAllowedToEndTripsEndingToday
             }
             LogbookUpdateError::TooFast(km, min) => LogbookCreateError::TooFast(km, min),
+            LogbookUpdateError::AlreadyFinalized => LogbookCreateError::AlreadyFinalized,
         }
     }
 }
@@ -546,6 +549,10 @@ ORDER BY departure DESC
             return Err(LogbookUpdateError::NotYourEntry);
         }
 
+        if self.arrival.is_some() {
+            return Err(LogbookUpdateError::AlreadyFinalized);
+        }
+
         let boat = Boat::find_by_id_tx(db, self.boat_id as i32).await.unwrap(); //ok
 
         if boat.amount_seats == 1 {